Table 4.

Common differential diagnoses

Differential diagnosis	Examples
Infection	Overwhelming sepsis (e.g. meningococcal sepsis)
	Atypical pneumonia
	Legionella infection
	Lyme's disease
	Leptospirosis
	Tuberculosis
	Bacterial endocarditis
	Mycotic aneurysms
	Haemolytic–uraemic syndrome
Collagen vascular disease	Systemic lupus erythematosus
	Rheumatoid arthritis
	Antiphospholipid syndrome
	Sjögren's syndrome
	Cryoglobulinaemia
Malignancy	Lymphoma/leukaemia
	Paraneoplastic syndromes
Other	Sarcoid
	Thrombotic thrombocytopenic purpura
	Cholesterol emboli